Medical injection device

ABSTRACT

The present invention relates to injection devices for injecting a dose of a medicament. The injection device ( 100 ) incorporates a housing ( 101 ), a needle assembly ( 150 ) and a cover ( 200 ). The needle assembly ( 150 ) comprises an injection needle ( 152, 153 ) accommodated in a needle container ( 151 ) having an opening which in a storage state of the injection device ( 100 ) is sealed by a film seal ( 155 ). The cover may include sections ( 201, 202 ) arranged movable relative to the housing ( 101 ). The injection device ( 100 ) is so configured that upon movement of the cover sections ( 201, 202 ) relative to the housing ( 101 ) the film seal ( 155 ) is changed from a sealing state to an unsealing state for shifting the injection device ( 100 ) into a ready-to-administer state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. §371 National Stage application ofInternational Application PCT/EP2011/074255 (WO 2012/089821), filed Dec.29, 2011, which claimed priority of European Patent Application10197464.0, filed Dec. 31, 2010; this application claims priority under35 U.S.C. §119 of U.S. Provisional Application 61/430,327 filed Jan. 6,2011.

FIELD OF THE INVENTION

The present invention relates to injection devices for injecting amedicament. In particular the present invention relates to single useinjection devices for injecting a medicament from a held cartridge andimprovements relating to the performance of such injection devices.

BACKGROUND OF THE INVENTION

In relation to some diseases patients must inject a medicament on aregular basis such as once weekly, once daily or even a plurality oftimes each day. In order to help patients overcome fear of needles,injection devices have been developed that involves auto-insertion ofthe needle which makes operation of an injection device as simple aspossible. Such devices are typically designed as auto-injectors whichprovide automatic expelling of the medicament. In order to perform aninjection, the user shall position the injection device onto theinjection site and activate the device. Such activation causes thedevice to insert a needle into the skin, eject a dose of the medicamentand subsequently move the needle into a shielded position.

For injection devices that use a cartridge without integrated injectionneedle, it is a requirement that the medicament container is connectedto an injection needle in order for the medicament to be injected intothe patient. The needle however must not be mounted prior to use as thiswill compromise the sterility of the needle and cartridge and could leadto contamination of both. The needle must therefore be mounted justbefore the device is used.

The procedure of mounting an injection needle to the device involvesextensive handling of the needle which can result in unintentionalneedle cuts, contamination or damaging of the needle. Furthermore theneedle handling can lead to users finding the device more difficult touse.

Designing the device to incorporate the needle will remove needlehandling, however existing needles are difficult to use as internalneedles, due to the design of their device interface, which typicallyrequires a turning motion for mounting and their packaging comprising aneedle container and a sterile barrier which under normal use areremoved manually prior to mounting.

One example of an auto-injector incorporating an injection needle thatis kept separate from the cartridge prior to use and which addresses thesterility issue is disclosed in WO 01/07104. In this reference, theneedle assembly comprises two separate resilient needle sheaths forrespectively protecting the front and rear needle. Typically, this typeof needle sheath is made from latex rubber. During use, the needlesheaths are penetrated by the respective needle sections. Althoughensuring sterility before use, the needle assemblies incorporatingflexible needle sheaths typically leads to an increase in expensesduring manufacture. In addition, mechanical impact during manufacture orduring handling may lead to the sheaths becoming prematurely penetratedthereby compromising sterility of the injection needle.

U.S. Pat. No. 5,829,589 discloses a pen needle magazine dispenser to bereceived in a cap of a medication delivery pen. A plurality of cavitiesare formed in the dispenser. Each cavity accommodates a pen needleassembly. A disc shaped label or sterility barrier provides sterilityfor unused pen needle assemblies. Although the label is claimed to offercontrolled breaking when an adaptor equipped delivery pen is pressedthrough the label the manual handling of the pen and the magazinedispenser does not provide for a user-friendly operation.

In a further reference, US2003/0144633 two example designs of a needleassembly are shown that involves a rear needle section of the injectionneedle that is kept in a sterile chamber by means of a film-type sealattached to the walls forming the chamber. The needle assembly isincorporated in an auto-injection device wherein a pre-stressed springis used to drive forward a container and subsequently drive forward apiston of the container during the expelling operation. Upon triggeringof the device, the container is driven forward so that the containerpenetrates through the film seal into the sterile chamber. This causesconnection between container and the rear portion of the injectionneedle. The needle assemblies involve additional openings whichnecessitates use of further sealing members. Further, the particulardesigns of the disclosed needle assemblies are not particularlywell-suited for use in connection with standard type injection devices,such as multi-use pen injectors where the needle handling is performedmanually. This makes the manufacturing of the disclosed needleassemblies particular expensive. In addition, by using the one and samespring for facilitating both the penetration of the film-type seal aswell as for injecting the medicament, an optimized operation of the twoparts of the operation is very difficult to achieve.

Having regard to the above-identified prior art devices, it is an objectof the present invention to provide an injection device incorporating astandard needle assembly of the conventional type used for multi-use peninjectors and which facilitates improved and consistent unsealing of thesealing member of the needle assembly.

Yet additional further objects of the invention are to provide measuresfor obtaining devices having a superior performance, providing easyoperation and, at the same time, enabling manufacture at a reduced cost.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present invention relates to an injection devicecomprising:

-   a) a housing,-   b) a cartridge arranged relative to the housing and defining a main    axis, the cartridge comprising an outlet covered by a cartridge    septum adapted to be pierced by an injection needle for establishing    fluid communication with the cartridge interior and comprising a    piston which is driveable along the main axis towards the outlet,-   c) a piston driver for engaging the piston and capable of being    actuated for driving the piston in a distal direction towards the    outlet,-   d) a needle assembly arranged at the distal end of the housing, the    needle assembly comprising an injection needle having front and rear    sections for respectively penetrating the skin of a subject user and    for piercing the cartridge septum, the needle assembly further    comprising a needle container accommodating the injection needle,    the needle container having an opening which in an initial state of    the injection device is sealed by a film seal for maintaining the    injection needle in a sterile condition, and-   e) a cover which in the initial state of the injection device is    held relative to the housing and which at least partly covers the    needle assembly, the cover being adapted for movement relative to    the housing,-   wherein the injection device defines an unsealing member which is    adapted to cause the film seal to change from a sealing state into    an unsealing state by relative movement between the needle assembly    and the unsealing member, and-   wherein relative movement between the cover and the housing causes    the film seal to change from the sealing state to the unsealing    state.

According to the aspect identified above, by configuring the device witha cover which may form part of the packaging of the device and which ismoved relative to the injection device prior to use, by utilizing therelative movement of one or more parts of the packaging when thepackaging is opened by the user gaining access to the device, themechanism for mounting the needle can be implemented in the packaging inwhich the device is delivered.

The said initial state of the injection device may correspond to astorage state where the cover is attached relative to the housing of theinjection device for enabling proper long-term storage conditions forthe injection device.

In the storage state of the injection device, the cover may be heldrelative to the housing in a first relative position wherein the coverat least partly covers the needle assembly. Upon movement between thecover and the housing from the first relative position to a secondrelative position the film seal is caused to shift from the sealingstate to the unsealing state. Hereby the injection device is shiftedinto a ready-to-administer state. During the relative movement betweenthe cover and the housing from the first relative position to the secondrelative position, the cover may remain continuously coupled with thehousing. Hence, from the storage state to the ready-to-administer statethe cover is not detached relative to the housing.

The cover may be connected to the housing of the injection device by acoupling mechanism which defines a pre-defined movement between thecover and the housing from the storage state to the state where the sealhas been shifted into the unsealing state.

In said unsealing state, the injection device has been shifted into aready-to-administer state. In the ready-to-administer state, the covermay be moved further relative to the housing for enabling the needlecontainer to be removed from the injection needle.

The injection device may be configured to enable manual actuation of thepiston driver to drive the piston towards the outlet subsequent to thecover being operated for changing the film seal from the sealing stateto the unsealing state. In some forms, the injection device is soconfigured that upon manual actuation the user presses forward thepiston driver during dose expelling operation. In other forms, theinjection device is so configured that a pre-tensed spring drivesforward the piston driver upon manual actuation of an activation member.Non-exhaustive examples of such activation member may be an activationbutton, a sleeve movably arranged relative to the housing, such as aneedle sleeve or a needle shield. In some forms, the manual actuation ofthe piston driver is prevented until the injection device has beenshifted into the ready-to-administer state whereupon actuation isenabled. In other forms, the manual actuation of the piston driver isprevented until the needle container is removed from the injectionneedle whereupon actuation is enabled.

In some embodiments, the needle container defines a sealed chamberwherein the injection needle is completely accommodated. The needlecontainer may incorporate a body having a cup shaped form and defining asingle sealed opening, wherein the single sealed opening is sealed bythe film seal when the injection device is in the storage state.

The film seal of the needle assembly may take form of a planar film,such as a paper seal which is adhered or otherwise sealingly attachedalong a rim section of an opening of the needle container. The needleassembly may form a standard needle package for use in connection withinjection pens which are commonly being used for administeringmedicaments for the treatment of diseases such as diabetes. Exemplaryneedle assemblies suitable for use in connection with the above aspectare disclosed in EP 279583 A2, WO 96/02290 A2 and WO 2004/004812 A1.

In some embodiments, the cover moves from a first position to a secondposition to cause the needle assembly and the unsealing member to moverelative to each other along the main axis to cause the film seal tochange from the sealing state to the unsealing state. In suchembodiment, the movement of the cover from the first position to thesecond position may be different than a purely axial movement, such asby a purely rotational movement, a combined rotational and axialmovement, or a sequence of axial and rotational movements.

In some embodiments, the front and rear needle defines a common axis. Inthe storage state of the device the common axis may be identical with alongitudinal axis of the cartridge, i.e. the main axis. In other forms,in the storage state the common axis is not identical with thelongitudinal axis of the cartridge. In such a configuration, the commonaxis and the longitudinal axis are brought into alignment when the coverand the housing is moved relatively from the first relative orientationto the second relative orientation.

The above mentioned coupling mechanism defining the pre-defined movementbetween the cover and the housing may in some embodiments involve arotational movement of the cover relative to the housing. This may beprovided by a mechanism which transfers the force exerted by the userfor operating the cover into a larger force for changing the film sealfrom the sealed state to the unsealed state. Thereby safe and effectiveunsealing of the film seal may be carried out where the film seal isremoved or ruptured in a consistent way. In addition, such solutionenables use of standard components such as standard needle assembliesand standard cartridges which provides for manufacture in acost-effective manner.

In some forms the cover moves from a first position to a second positionto cause the film seal to change from the sealing state to the unsealingstate and wherein a force exerted by the user for operating the coverrelative to the housing is transformed to a force of greater magnitudefor effecting relative movement between the needle assembly and theunsealing member along said main axis.

In some embodiments, the cover forms a cap which attaches to or is beingheld relative to a distal end of the housing of the injection devicewhen the device is in the initial state.

The cap and the housing may be configured to form a track and grooveconnection. In such configuration, a relative rotational movementbetween the cap and the housing is transformed into a linear movementdefined by means of said track and groove connection for causingrelative axial movement between the needle assembly and the unsealingmember.

In some forms, the injection device includes a pre-stressed spring whichreleases upon operation of the cap relative to the housing, wherein thespring, when released, drives the needle assembly and the unsealingmember relative to each other for changing the film seal from thesealing state to the unsealing state.

In some forms, the cover at least in part forms a packaging which in thestorage state of the injection device accommodates the housing of theinjection device. The cover may define a first cover section whichswivels relative to the housing along a second axis, where the secondaxis is substantially orthogonal to the main axis.

In some forms, the first cover section forms a lever arm which uponoperation causes the needle assembly and the unsealing member to moverelative to each other.

In addition to the first cover section, the cover may further define asecond cover section wherein the first and second cover sections formscooperating shells for accommodating the housing and the needleassembly. The first and the second cover section may be configured torotate relative to each other around a third axis. The second axis andthe third axis may in some embodiments define parallel axes.

In some embodiments, relative movement between the cover and the housingfurther causes the rear section of the injection needle to pierce thecartridge septum for establishing fluid communication with the interiorof the cartridge.

In still other embodiments, the cover is configured for being separatedfrom the housing subsequent to the cover being operated for changing thefilm seal from the sealing state to the unsealing state but prior tomanual actuation of the piston driver for driving the piston towards theoutlet. The cover may in further embodiments be so configured that whenthe cover is separated from the housing, the needle container isautomatically separated from the injection needle whereby access to thefront needle is enabled. The cover may in some forms be configured forbeing separated relative to the housing of the injection device afterthe injection device has been brought into the ready-to-administerstate. In some forms the needle container is mounted within the cover sothat the needle container is removed from the injection needle as thecover is separated from the housing.

In some embodiments, the unsealing member may be formed as a member heldin the housing of the injection device, either as a separate member oras a part formed by the housing, or alternatively, the cartridge itselfmay define the unsealing member. The unsealing member may includefeatures enabling a consistent unsealing, e.g. for obtaining safe andeffective rupturing or peeling of the film seal from the needlecontainer, by including one or more cutting surfaces with sharp orpoint-like features or the like.

Some variants may use cartridges made of glass. Other embodiments mayincorporate a cartridge being made of a synthetic resin or the like. Inaddition, some embodiments may use a cartridge having a cartridge bodywhich at the same time performs as a housing of the injection device.

The housing of the device may in some embodiments be formed to define adistal end and a proximal end. In some embodiments, the overall shape ofthe injection device may be formed to exhibit a pen-shape.

The device may in some embodiments be formed as a disposable (singleuse) device which in one form may be adapted to deliver a single dose ofa medicament for subsequent disposal. Such device may have a medicamentcartridge irremovably accommodated inside the housing. In some forms,the device may be adapted to dispense either a pre-determined fixed doseof medication through an expelling operation. In other forms, the devicemay be configured to enable the setting of the size of a dose intendedfor subsequent injection during an expelling operation.

As used herein, the term “distal end” of the injection device or acomponent thereof may refer to that end of the device or the componentwhich is closest to the dispensing end of the device. The term “proximalend” of the injection device or a component thereof may refer to thatend of the device or the component which is furthest away from thedispensing end of the device.

As used herein, the term “medicament” is meant to encompass anymedicament-containing flowable drug capable of being passed through adelivery means such as a hollow needle or cannula in a controlledmanner, such as a liquid, solution, gel or fine suspension. Alsolyophilized drugs which prior to administration are dissolved into aliquid form is encompassed by the above definition. Representativemedicaments includes pharmaceuticals such as peptides, proteins (e.g.insulin, insulin analogues and C-peptide), and hormones, biologicallyderived or active agents, hormonal and gene based agents, nutritionalformulas and other substances in both solid (dispensed) or liquid form.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in further detail with reference tothe drawings in which:

FIG. 1 a shows a cross sectional view of a first embodiment of aninjection device 100 and a needle assembly in a packaging 200 accordingto the invention, in an initial storage state,

FIGS. 1 b-1 f show cross sectional views of different operating stagesduring unpackaging of the injection device 100 shown in FIG. 1 a,

FIGS. 2 a-2 g show different operating stages of a second embodiment ofan injection device 100′ accommodating a needle assembly 150′ and havinga cap member 170′, the views showing side views of a sectional cutthrough housing 101′,

FIGS. 3 a-3 g show cross sectional views of the second embodiment of theinjection device 100′ in different operating stages corresponding tooperating stages shown in FIGS. 2 a-2 g,

FIGS. 4 a-4 e show side views of different operating stages of a thirdembodiment of an injection device 100″ accommodating a needle assembly150″ and having a cap member 170″, and

FIGS. 5 a-5 e show cross sectional views of the third embodiment of aninjection device 100″, the views of the different operating stagescorrespond to the operating stages shown in FIGS. 4 a-4 e.

FIG. 1 a shows a cross sectional view of a first embodiment of a medicalinjection device 100 for medically injecting a pre-determined amount ofa liquid medicament. FIG. 1 a shows the injection device 100 in astorage condition. The depicted embodiment shows a disposable devicewhich is adapted to administer a fixed dose of medicament uponactivation for subsequent disposal. The embodiment shows an injectiondevice in the form of an auto-injector which provides automaticinjection of medicament from a standard cartridge 120. The cartridge 120has a piston arranged internally which is arranged slideably along acentral axis of the cartridge for being driven towards an outlet of thecartridge. A piercable septum seals the outlet of cartridge 120 prior touse thereof, the septum being adapted to be pierced by an injectionneedle for establishing fluid communication with the medicament of thecartridge.

FIG. 1 a further shows a needle assembly 150 comprising a needlecontainer 151 accommodating a double pointed injection needle 152, 153.The injection needle includes a needle cannula 153 having a front and arear needle section and a needle hub 152 which is used for connectingthe injection needle to the main part of the injection device 100. Theneedle container 151 has an proximally facing opening which is sealed bya sterility seal 155, such as a planar film seal, for example in theform of a paper seal which is attached along a rim section of an openingof the needle container 151. The shown needle assembly 150 forms astandard needle package for use in connection with injection pens whichare commonly being used for administering medicaments for the treatmentof diseases such as diabetes.

In FIG. 1 a, a cap member 170 is depicted that cooperates with housing101 and is adapted to slide axially relative to housing 101. With thedevice in the storage condition, the cap member 170 holds the completeneedle assembly with the film seal intact.

FIG. 1 a further shows a packaging in the form of a cover 200 havingcover sections 201 and 202. In the storage state of the device, thecover 200 holds the needle assembly 150 separate from the main part ofthe injection device 100 and hence separate from the cartridge 120. Thefilm seal 155 is still attached to needle container 151 hence providingstorage of the injection needle in the sterilized state. In the storagestate, internally in cover 200, the needle assembly 150 and the mainpart of the injection device 100 are arranged such that the sterilityseal 155 opposes an unsealing member 115 associated with the cartridgeseptum of cartridge 120.

For a comparison of the injection device 100 in the ready to use state,i.e. where the injection needle 153 is attached to the cartridge 120,reference is made to FIG. 1 f.

In FIGS. 1 a through 1 d the drawings show the operation of unsealingthe needle container for enabling connection of the injection needle152/153 with the injection device 100 by moving the upper cover section201 with respect to the bottom cover section 202 from the fully closedconfiguration to the fully open configuration.

As shown in FIG. 1 b, cover sections 201 and 202 connects by means of afirst swivel joint so that the top cover section 201 may be rotatedapproximately 180 degrees relative to the bottom cover section 202around a first swivel joint 204 from the fully closed configuration tothe fully open configuration. Top cover section 201 further forms anaxle stub 205 which cooperate with a recess 105 in housing 101 ofinjection device 100. In the depicted embodiment the top cover 201defines an approximate “L” shaped member having a relatively long firstarm and a relatively short second arm arranged approximately 90 degreesapart. The first swivel joint 204 is disposed where the two armsintersect and the axle stub 205 is arranged at the free end of thesecond arm. The bottom cover section 202 is adapted to hold the capmember 170 so that the cap member 170 and the housing 100 cannot befurther separated. Due to the geometry of the top cover section 201,with the layout of first swivel joint and axle stub 205, the top cover201 forms a lever arm which when top cover 201 is initially opened itacts to push housing 101 towards the cap member 170, i.e. causing thedevice formed by housing 101 and 170 to become shorter, cf. FIG. 1 b andFIG. 1 c.

As the housing 101 is moved relatively to cap member 170 the unsealingmember 115 is pushed to protrude through film seal 155 enabling the rearsection of the injection needle 153 to connect to the cartridge 120,i.e. by penetrating the septum of the cartridge. In the shownembodiment, this occurs shortly after the top cover has moved past theposition shown in FIG. 1 c. Due to the lever arm construction of thecover sections, a considerable force may be provided to enable the filmseal to be securely penetrated by the unsealing member. When the topcover 201 is moved further towards the fully open position, the assemblyformed by housing 101 and cap member 170 is retracted a short distanceand lifted from the bottom cover section 202. Due to the joint formed byaxle stub 205 and recess 105 forming a detachable connection, when thecover sections are positioned in their open configuration, the housing101 and cap member 170 of the injection device 100 may be easilyseparated from the casing sections 201 and 202. In this state, as shownin FIG. 1 e, the device 100 is prepared for use (ready-to-administercondition). After initially removing the cap member 170 the device is ina ready-to-injection condition (see FIG. 1 f). As the needle container151 is attached to the cap member 170, separating the cap member 170from the housing 101 causes the needle container 151 to separate fromthe main part of the injection device 100 as well. In the depictedembodiment, the cap member 170 forms a security cap. In otherembodiments, the cap member 170 may be omitted. In such embodiments, thebottom cover section 201 may be adapted to initially hold the needlecontainer 151 such that separating the device 100 from the two casingsections 201 and 202 causes the needle container 151 to automaticallyseparate from the main part of the injection device 100.

The ready-to-inject state of the injection device 100 where the capmember 170 has been removed is shown in FIG. 1 f. As noted above theinjection device may be formed as an auto-injector which for exemplarypurposes will be shortly described. In the depicted embodiment, thepiston driver 110 is biased by a pre-stressed spring 111. Beforeactuation, the piston driver 110 is held in a retracted position due tobeing retained by retaining ledges of a retaining member 112. A needleshield 130 is initially positioned in an extended position (biased by anot shown spring) so as to cover the front section of the needle 153.When the injection device is positioned at an injection site, by forcingthe device 100 against the skin, the needle shield 130 is forcedbackwards. The needle shield 130 includes activating surfaces adapted tocooperate with the retaining member 112 such that when the needle shieldhas been pushed sufficiently proximally for the front section of theinjection needle 153 to be inserted into the skin of the patient, theretaining member 112 releases the piston driver 110. Due to the energystored in the pre-stressed spring 111, the piston driver 110 is drivenforward to expel the pre-defined dose. After dose injection, theinjection device 100 may be withdrawn from the skin, and the injectiondevice may be discarded after re-positioning the cap member 170 and/orthe cover sections 201 and 202.

In the shown embodiment the injection needle 152/153 is attached to themain part of the injection device 100 by means of a purely translationmovement involving no rotation. The needle mounting surfaces of theneedle hub 152 and/or the mounting surface of the injection device(un-referenced) may be formed to allow connection by a non-rotationalrelative linear movement for example by designing the needle hub and/orthe mounting surface to obtain a snap connection. As an example, theprotrusions of the needle hub of the injection needles shown in WO2004/004812 A1 can be used as one part of a snap lock to lock theinjection needle to the injection device, thus eliminating the need fora rotating movement during mounting of the needle.

As discussed above, the film seal 155 is broken as the unsealing member115 protrudes through the opening formed in needle container 151.Alternatively, or in addition, the pull tab formed in the film seal ofconventional needle containers may be attached to the top cover section201 by means of a peel member 206 formed to protrude from the innersurface of top cover section 201 towards the film seal 155 of the needleassembly 150, see FIGS. 1 a and 1.b. As the top cover section 201 isinitially rotated relative to bottom cover section 202, the peel member206 peels off the film seal 155 by moving the film seal in a directionapproximately transversely to a centre axis of the needle assembly 150.Hence, the peel member 206 may fully or partly peel off the film sealfrom the rim of the needle container 151 to enable easy penetration ofthe unsealing member 115 or alternatively allow for the cartridge 120 toprotrude directly into the interior of the needle container 151.

Depicted in FIGS. 2 a-2 g and FIGS. 3 a-3 g a second embodiment of aninjection device 100′ is shown. As for the first embodiment, the variousdrawings show the injection device 100′ in different stages duringunsealing and mounting of an injection needle 152′/153′ relative to themain part of the injection device 100′. FIGS. 2 a through 2 g show sideviews of the device 100′ with a sectional cut through housing 101′ toallow inspection of a track and groove connection between the housing101′ of the injection device and a cover defining a cap member 170′which attaches to a distal end of the injection device 100′. FIGS. 3 athrough 3 g are centre cross sectional views of the injection device100′ corresponding to the states shown in FIGS. 2 a through 2 grespectively.

The second embodiment of the injection device 100′ shows a manualinjector having an actuating button 103′ arranged at the proximal end ofhousing 101′ which allows the piston of cartridge 120′ to be drivenmanually for expelling the contents of the cartridge. In the storagestate of the device shown in FIGS. 2 a and 3 a, the cap member 170′holds a needle assembly 150′ which generally correspond to the needleassembly 150 shown in the first embodiment. The cap member 170′ servesas a tool for allowing the film seal 155′ of the needle assembly 150′ tobe changed from the sealed state to an unsealed state by rotating thecap member 170′ relatively to housing 101′. To facilitate ergonomicoperation, in particular for users having limitations in dexterity, thecap member 170′ includes a pair of wings which are easily gripped by onehand while the housing 101′ may be firmly gripped by the other hand.

As noted above a track and groove connection is formed between capmember 170′ and housing 101′. This track and groove connection definesthe relative motion between the two components. In the shown embodiment,the cap member 170′ has a proximal section which is inserted internallyin a distal part of housing 101′. A protrusion 102′ protrudes radiallyinwards from housing 101′ to cooperate with a track 171′ formed in anexterior part of the cap member 170′. The cap member may have an arrowindicator 172′ formed on a visible part thereof as shown on thedrawings. The arrow indicator 172′ is indicative of the intended way ofoperation of the cap member 170′ relative to housing 101′.

As shown in FIG. 3 a which shows the device in the initial storagecondition, the needle assembly is arranged separated from the cartridge120′ and separated from unsealing member 115′. Hence the injectionneedle 152′/153′ is stored in a sterile condition due to the film seal155′ being intact.

The track 171′ has a shape which roughly corresponds to the shape of thearrow indicator 172′. In the shown embodiment, the cap member 170′ isinitially rotated which induces an axially movement of cap member 170′in the proximal direction (shown in FIGS. 2 a-2 d and 3 a-3 d). Duringthis rotation, the assembly formed by housing 101′ and cap member 170′is made shorter. Due to the relative axial motion between cap member170′ and housing 101′, the needle container 151′ is pressed towards theunsealing member 115′. Due to the force exerted on the cap member 170′by the rotational movement is transferred to a larger force in the axialdirection the unsealing member protrudes relatively easy into the cavityformed by the needle container 151′ thereby rupturing the film seal 155′and allowing the rear section of the injection needle 153 to penetratethe cartridge septum (see FIG. 3 d).

The track 171′ defines that further rotation is not possible. However,due to a segment of track 171′ extending in the axial direction, the capmember 170′ may be moved in the distal direction thereby separating thecap member 170′ from the housing 101′ of injection device 100′ (seeFIGS. 3 e and 3 f). In the shown embodiment, the cap member 170′ firmlygrips the needle container 151′ which thereby is withdrawn from thehousing 101′ as the cap member 170′ is removed. As shown in FIGS. 2 fand 3 f, an inner cap 156′ protects the needle before administration isto be performed. After removal of inner cap 156′ the injection device100′ is in a ready-to-inject condition (see FIGS. 2 g and 3 g).

As in the first embodiment, the needle hub 152′ and a mounting surfaceof the injection device 100′ may form a snap connection. Alternatively,the connection may be provided as a threaded connection or as a bayonetconnection. The track 171′ may be formed to allow the rotationalcoupling of such threaded connection or bayonet connection so that therotation of cap member 170′ relative to housing 101′ ensures the correctattachment between the needle hub 152′ and the needle mounting surfaceof the device.

After administration, the cap member 170″ may be re-attached to thehousing 101″ for safe disposal of the used injection device 100″.

FIGS. 4 a-4 e and FIGS. 5 a-5 e shows a third embodiment of an injectiondevice 100″. As for the first and second embodiments, the variousdrawings show the injection device 100″ in different stages duringunsealing and mounting of an injection needle 152″/153″ relative to themain part of the injection device 100″. FIGS. 4 a through 4 e showexternal side views of the device 100″ and a cover defining a cap member170″ which attaches to a distal end of the injection device 100″. FIGS.5 a through 5 e are centre cross sectional views of the injection device100″ corresponding to the states shown in FIGS. 4 a through 4 erespectively.

The third embodiment of the injection device 100″ shows an auto-injectorhaving an actuating button 103″ arranged at the proximal end of housing101″ configured for being manually actuated. Upon manual actuation thedevice is triggered allowing the piston of cartridge 120″ to be drivenautomatically by a pre-stressed spring for expelling the contents of thecartridge. Although only schematically described, the shown thirdembodiment of the auto-injector involves auto-insertion of the injectionneedle at an injection site when the injection device 100″ is triggered.This occurs by moving the cartridge 120″ with the injection needle152″/153″ attached in a distal direction internally in housing 101″.

In the storage state of the device shown in FIGS. 4 a and 5 a, the capmember 170″ holds a needle assembly 150″. The needle assembly may be ofthe kind shown in WO 03/045480 A1 which discloses a needle having aneedle shield being biased by a spring element for maintaining theinjection needle hidden prior to use and which locks in the extendedposition after use. As shown in FIG. 5 a which shows the device 100″ inthe initial storage condition, the needle assembly 150″ is arrangedseparated from the cartridge 120″ and separated from unsealing member115″. Hence the injection needle 152″/153″ is stored in a sterilecondition due to the film seal 155′ being intact.

A not shown connection between cap member 170″ and housing 101″ definesthe two parts to be initially rotated. After the end of the rotation,the cap member 170″ may be removed from housing 101″.

The cap member 170″ includes a mechanism for providing the unsealingaction for the film seal 155″ of the needle assembly 150″ upon rotationof cap member 170″ relative to the housing 101″. The mechanism includesa pre-stressed spring 190″ dedicated to the unsealing action forremoving and/or penetrating and/or rupturing the film seal of the needleassembly 150″. The distal end of the pre-stressed spring 190″ is held bythe cap member 170″ whereas the proximal end of the spring 190″ actsupon an axially movable member 180″. The axially movable member 180″ ismounted relative to the needle container 151″.

Upon rotation of cap member 170″ relative to housing 101″ from a firstposition shown in FIGS. 4 a and 5 a to a second position shown in FIGS.4 c and 5 c the axially movable member 180″ is released from an initialdistal position. Due to the spring force of spring 190″ the axiallymovable member 180″ is forced in the proximal direction which pressesthe needle assembly 150″ in the proximal direction. The spring forcethereby forces the unsealing member 115″ to enter into the cavity formedby the proximal end of the needle container 151″ thereby changing thefilm seal 155″ from the sealed state to the unsealed state. By thismechanism a relatively low force required for rotating the cap member170″ relative to the housing 101″ is transformed into a relatively highforce in the axial direction. By choosing the spring constant of thespring 190″ and the point of impact, the pre-defined impact needed forthe unsealing action may be optimally ensured. In this embodiment, themovement of the needle assembly 150″ relative to the housing 101″ alsoincorporates needle penetration into the cartridge septum.

As shown in FIGS. 4 d and 5 d, the cap member 170″ may subsequently tothe unsealing action be moved in the distal direction thereby separatingthe cap member 170″ from the housing 101″ of injection device 101″ (seeFIGS. 4 e and 5 ef). In the shown third embodiment, the cap member 170″and the axially movable member 180″ holds the needle container 151″which thereby is withdrawn from the housing 101″ as the cap member 170″is removed.

As shown in FIGS. 4 e and 5 e, a needle shield 156″ protrudes slightlyfrom the distal end of the housing 101″. This needle shieldautomatically retracts relative to the housing when the injection device100″ is pressed against an injection site. Hence, FIGS. 4 e and 5 e showthe injection device 100″ in the ready-to-inject condition.

After administration, the cap member 170″ may be re-attached to thehousing 101″ for safe disposal of the used injection device 100″.

It should be noted that in the above described embodiments, the type ofinjection devices shown serve mainly as exemplary embodiments forexplaining the function of the needle unsealing procedure. In the shownembodiments, injectors having auto-injection functionality and manualinjectors are used but these may be interchanged. In addition, inalternative embodiments, other types of injectors having higher or lowerlevels of automation may be used, e.g. injectors having auto-insertionor auto-retraction of the needle as well as manual insertion andretraction of the injection needle. In the injectors, the cartridgeaccommodated in the device may be fixedly attached inside the housing ormay be mounted slideably relative to the housing.

Some preferred embodiments have been shown in the foregoing, but itshould be stressed that the invention is not limited to these, but maybe embodied in other ways within the subject matter defined in thefollowing claims.

The invention claimed is:
 1. An injection device comprising: a housing,a cartridge arranged relative to the housing and defining a main axis,the cartridge comprising an outlet covered by a cartridge septum adaptedto be pierced by an injection needle for establishing fluidcommunication with a cartridge interior and comprising a piston which isdriveable along the main axis towards the outlet, a piston driver forengaging the piston and capable of being actuated for driving the pistonin a distal direction towards the outlet, a needle assembly arranged atthe distal end of the housing, the needle assembly comprising theinjection needle having front and rear sections for respectivelypenetrating skin of a subject user and for piercing the cartridgeseptum, the needle assembly further comprising a needle containeraccommodating the injection needle, the needle container having anopening which in a storage state of the injection device is sealed by afilm seal for maintaining the injection needle in a sterile condition,and a cover arranged relative to the housing and configured for relativemovement, wherein, in the storage state of the injection device, thecover is held relative to the housing in a first relative orientationwherein the cover at least partly covers the needle assembly, whereinthe cover at least in part forms a packaging which in the storage stateof the injection device accommodates the housing of the injectiondevice, and the cover defines a first cover section which swivelsrelative to the housing along a second axis, the second axis beingsubstantially orthogonal to the main axis, wherein the injection devicedefines an unsealing member which is adapted to cause the film seal tochange from a sealing state into an unsealing state by relative movementbetween the needle assembly and the unsealing member, wherein the firstcover section forms a lever arm which upon operation causes the needleassembly and the unsealing member to move relative to each other, andwherein relative movement between the cover and the housing from thefirst relative orientation to a second relative orientation causes thefilm seal to change from the sealing state to the unsealing state forshifting the injection device into a ready-to-administer state, thecover being continuously coupled with the housing during said relativemovement between the cover and the housing from the first relativeorientation to the second relative orientation.
 2. An injection deviceas in claim 1, wherein the needle container defines a sealed chamberwherein the injection needle is completely accommodated, the needlecontainer forming a body having a cup shaped form and defining a singlesealed opening, wherein the single sealed opening is sealed by said filmseal when the injection device is in said storage state.
 3. An injectiondevice as in claim 1, wherein the injection device is configured toenable manual actuation of the piston driver to drive the piston towardsthe outlet subsequent to the cover being operated for changing the filmseal from the sealing state to the unsealing state.
 4. An injectiondevice as in claim 1, wherein the cover moves from a first position to asecond position to cause the needle assembly and the unsealing member tomove relatively to each other along said main axis to cause the filmseal to change from the sealing state to the unsealing state and whereinthe movement of the cover from the first position to the second positionis different than a purely axial movement.
 5. An injection device as inclaim 1, wherein the cover moves from a first position to a secondposition to cause the film seal to change from the sealing state to theunsealing state and wherein a force exerted by the user for operatingthe cover relative to the housing is transformed to a force of greatermagnitude for effecting relative movement between the needle assemblyand the unsealing member along said main axis.
 6. An injection device asin claim 1, wherein the cover forms a cap which attaches to the distalend of the housing when the injection device is in the storage state. 7.An injection device as in claim 6, wherein the cap and the housing formsa track and groove connection and wherein a relative rotational movementbetween the cap and the housing is transformed into a linear movementdefined by said track and groove connection for causing relative axialmovement between the needle assembly and the unsealing member.
 8. Aninjection device as in claim 6, wherein the injection device includes apre-stressed spring which releases upon operation of the cap relative tothe housing, wherein the spring, when released, drives the needleassembly and the unsealing member relative to each other for changingthe film seal from the sealing state to the unsealing state.
 9. Aninjection device as in claim 1, wherein the cover further defines asecond cover section wherein the first and second cover sections formscooperating shells for accommodating the housing and the needleassembly.
 10. An injection device as in claim 1, wherein relativemovement between the cover and the housing further causes the rearsection of the injection needle to pierce the cartridge septum.
 11. Aninjection device as in claim 1, wherein the cover is configured forbeing separated from the housing subsequent to the cover being operatedfor changing the film seal from the sealing state to the unsealing statebut prior to actuation of the piston driver for driving the pistontowards the outlet.
 12. An injection device as in claim 11, wherein thecover is configured for removing the needle container from the injectionneedle as the cover is separated from the housing.